Many philosophical accounts of manipulation are blind to the extent to which actual people fall short of the rational ideal, while prominent accounts in political science are under-inclusive. We offer necessary and sufficient conditions – Suitable Reason and Testimonial Honesty – distinguishing manipulative from non-manipulative influence; develop a ‘hypothetical disclosure test’ to measure the degree of manipulation; and provide further criteria to assess and compare the morality of manipulation across cases. We discuss multiple examples drawn from politics and from public (...) policy with particular attention to recent debates about the ethics and politics of nudge. (shrink)